Mulching is an effective way of insulating and protecting delicate plant root systems against harsh weather conditions. It works as a barrier that improves the soil's nutrient profile. Mulching also reduces erosion while enhancing the soil’s ability to hold more moisture.

Two of the most popular mulching types of mulch are organic and inorganic mulch. Organic mulch is made from biodegradable materials such as grass clippings, wood chips, dried leaves, and straws. On the other hand, inorganic mulch is comprised of river rock, stone, or crushed gravel.

But did you know that there is such a thing as plastic mulching too? What is plastic mulch and how is it any different from organic and inorganic mulch? More importantly, what are the pros and cons of using plastic mulch? Continue reading below to find out!

What is Plastic Mulch?

Plastic mulch is considered as a type of inorganic mulch. This type of mulching utilizes polyethylene film to shield plants from the elements. It was in the 1950s when plastic mulching became popular among US growers. Plastic mulching was used in commercial berry and vegetable production.

However, this method is now being adapted to home gardens too. The polyethylene film is usually a sheet of black plastic and it works the same way as organic mulch, the film insulates the soil, prevents soil erosion, and reduces moisture evaporation.

While plastic mulching certainly has its benefits, it’s important to dispose of the mulching material properly to reduce its effects on the environment. The fact is, the use of plastic films as mulch material raises environmental concerns because plastic is a type of petroleum product. Apart from utilizing a lot of energy to make plastic materials, these are difficult to recycle too.

2 Basic Types of Plastic Mulching

There are 2 basic types of plastic mulching: black polyethylene film and clear polyethylene. The black plastic film is ideal for eliminating weeds, warming up the soil during the cold season, as well as retaining the soil’s moisture. On the other hand, the clear plastic film works best for warming up the soil and encouraging faster growth early in the growing season. Clear plastic film, however, isn’t as effective when it comes to suppressing weed growth.

The Benefits of Using Plastic Mulching

Improves Soil Structure

Using plastic mulching helps prevent soil from clumping together into a compacted mess. The material traps moisture and heat, which limits the loss of plant nutrients. Of all the mulching materials available on the market, plastic mulch is the most restrictive so it pairs well with a drip irrigation method. In addition, the plastic film discourages people and pets from walking into the area, which further enhances the structure of the soil.

Insulates the Soil

Most plants are temperature sensitive, vegetables, in particular, cannot stand the winter cold. One of the reasons why growers use mulch is to help the soil retain heat as the cold months set in. Inorganic mulch like plastic mulch warms up the soil up to 5 degrees Fahrenheit. Plastic mulching regulates the soil temperature evenly, insulating temperature sensitive plants during the cooler months.

Fruit-bearing trees and tender perennials are more likely to break from their winter dormancy by using plastic mulch too. Plastic mulch is also effective in protecting trees and shrubs from winter damage.

Effective Weed Control

Is your garden plagued by weeds? If you don’t get rid of weeds every day, they will take over the garden in no time at all. Daily weeding can be a taxing chore for most gardeners, especially growers with back problems.

Plastic mulch suppresses weed growth effectively and it does so in a large expanse of space. When installed in the garden, plastic mulch prevents weeds from getting the sunlight needed for photosynthesis. When the weeds are deprived of sunlight, they die, which saves you the hassle of pulling weeds individually by hand.

Earlier Crop Growth

Using plastic mulching allows you to grow your crops early in the season. Because mulching warms up the soil, you can plant warm season crops up to three weeks earlier than the crops’ growing season.

The same thing cannot be said for organic mulch. Since plastic mulching does a better job of trapping heat into the soil, the soil warms up rapidly, providing the best growing conditions for warm season vegetables.

Higher Crop Quality

Want to grow high-quality crops? Using plastic mulching is key to better quality fruits and vegetables. The plastic mulch acts as a barrier that protects the fruits from getting in contact with the soil. This will inhibit the growth and spread of diseases and rot. And since the fruits are not in direct contact with the soil, they grow much more cleanly.

Reduces the Risk of Root Damage

Using plastic mulching eliminates the need for continuous cultivation except in between the rows of plastic. Since the soil remains undisturbed, the plant roots are able to grow and spread into the ground deeply and efficiently.

The fact is, cultivation is one of the major causes of root damage. But if your garden is prone to weeds, you don’t have much of a choice but to cultivate the soil. Using plastic mulching means the crops grow weed-free so there is no need to disturb the ground!

The Drawbacks of Using Plastic Mulch

It’s not Eco-friendly

Unlike organic mulch, plastic mulch is not biodegradable. It doesn't break down completely so it ends up in landfills. Plastic products are derived from petroleum-based materials, which are not only costly to produce but also bad for the environment.

Also, because the plastic mulch isn’t biodegradable, it has to be removed from commercial fields yearly, a practice that’s quite costly itself.

Hard to Dispose Of

The disposal of plastic mulch is problematic because 1) removal from fields requires specialized equipment and 2) plastic products are generally hard to dispose of. Unfortunately, most landfills require extra payment for plastic disposals, which adds to the overall cost of using plastic mulching.

Excessive Heat

While black plastic mulch warms up the soil effectively, altering the soil temperature isn’t advisable for all crops. Some crops are quite sensitive to soil temperature so warming up the soil may backfire, there is just no way to control the rising soil temperature. Black plastic mulching is only advisable to use for heat-loving vegetables like melons, tomatoes, peppers, and other summer crops. Never use black plastic mulch for growing cool-season crops, such as lettuce, peas, and tubers. Excessive heat will kill these crops.

Excessive Moisture

There are times when excess moisture is a bad thing. Plastic mulch does an excellent job of trapping moisture and minimizing the risk of water evaporation. However, it’s much easier to overwater and drown the crops due to excess moisture. Also, growers have to install soaker hoses or drip irrigation around each plant to control the moisture and prevent crops from drowning. Damp growing conditions could also lead to infestations and diseases.

Plastic mulching has its own benefits and drawbacks. As long as you know how to use (and dispose of) plastic mulching properly, you can maximize its benefits without worrying about the drawbacks! For more gardening resources, subscribe to our mailing list!